Assessment of tumor morphology on diffusion‐weighted (DWI) breast MRI: Diagnostic value of reduced field of view DWI

Abstract

PURPOSE To compare the diagnostic value of conventional, bilateral diffusion-weighted imaging (DWI) and high-resolution targeted DWI of known breast lesions. MATERIALS AND METHODS Twenty-one consecutive patients with known breast cancer or suspicious breast lesions were scanned with the conventional bilateral DWI technique, a high-resolution, reduced field of view (rFOV) DWI technique and dynamic contrast enhanced MRI (3.0 T). We compared bilateral DWI and rFOV DWI quantitatively by measuring the lesions’ ADC values. For qualitative comparison, three dedicated breast radiologists scored image quality and performed lesion interpretation. RESULTS In a phantom, ADC values were in good agreement with the reference values. Twenty-one patients (30 lesions: 14 invasive carcinomas, 10 benign lesions (of which 5 cysts), 3 high risk and 3 in situ carcinomas) were included. Cysts and high-risk lesions were excluded from the quantitative analysis. Quantitatively, both bilateral and rFOV DWI measured lower ADC values in invasive tumors than other lesions. In vivo, rFOV DWI gave lower ADC values than bilateral DWI (1.11× 10−3 mm2/s vs. 1.24 × 10−3 mm2/s, P=0.002). ROIs were comparable in size between the two techniques (2.90 vs. 2.13 cm2, P=0.721). Qualitatively, all three radiologists scored sharpness of rFOV DWI images as significantly higher than bilateral DWI (P ≤ 0.002). ROC curve analysis showed a higher AUC in BI-RADS classification for rFOV DWI compared to bilateral DWI (0.71 to 0.93 vs. 0.61 to 0.76, respectively). CONCLUSION Tumor morphology can be assessed in more detail with high-resolution DWI (rFOV) than with standard bilateral DWI by providing significantly sharper images.

Diffusion-weighted breast MRI: Clinical applications and emerging techniques

“…This approach must either suppress the surrounding regions (outer volume suppression [OVS]) or excite only the target region (inner volume excitation [IVI]). The latter approach (IVI) has found application to breast cancer in a range of studies using a two‐dimensional (2D) spectral‐spatial excitation . rFOV is highly applicable for breast lesion assessment where delineation of lesion borders and heterogeneity separate from the surrounding fibroglandular or adipose tissue can be challenging with conventional EPI, Figure .…”

Clinical Breast MR Using MRS or DWI: Who Is the Winner?

“…Spatial resolution and image quality are increasing, allowing also for a more detailed morphology evaluation (56, 57). As a matter of fact, authors have positively tried to integrate information coming from DWI into the Breast Imaging Reporting and Data System BI-RADS (58).…”

Comparison of reduced field‐of‐view diffusion‐weighted imaging (DWI) and conventional DWI techniques in the assessment of rectal carcinoma at 3.0T: Image quality and histological T staging

“…SS‐EPI has been increasingly used for detection/characterization of rectal neoplasms and monitoring of responses to neoadjuvant chemotherapy . However, the full field‐of‐view (fFOV) DWI sequence may produce susceptibility artifacts, distortion, and blurring because this sequence is particularly sensitive to off‐resonance, given the narrow bandwidth along the phase‐encoding direction . Specific techniques are available to address these problems, such as reversed‐phase‐encoding sequences to alleviate susceptibility‐induced distortions and twice‐refocused sequences to reduce eddy current‐induced distortions …”